Apparatus for the production of flat metal sheets, particularly tin plate sheets

ABSTRACT

An apparatus for the continuous production of tin plate sheet metal including a spool of sheet metal, an unrolling device carrying the spool, a strip of sheet from the spool, a driving device advancing the strip, a welding device, an accumulator for the strip, a tensioning device composed of a braking means and a traction means for maintaining the strip taut during its passage in the apparatus, a degreasing device, a pickling device, rinsing vats, an electric tinning device, for applying a tin coating on the strip, a drying device, a rollers smoothing device into which the strip of metal sheet passes, a re-fusing device of the tin coating, a hole detector and a guillotine for cutting the strip.

mam States mm [72] Inventor Willy Charles de Laminne Liege, Belgium [21]Appl, No. 620,528

[22] Filed Mar. 3, 1967 [45] Patented Dec. 14, 1971 [73] AssigneeCockerill-Ougree-Providence et Esperance- Longdor en abrege Cockerlll"Seraing-lez-Liege, Belgium [54] APPARATUS FOR THE PRODUCTION OF FLATMETAL SHEETS, PARTICULARLY TIN PLATE SHEETS 1 Claim, 2 Drawing Figs.

[52] U.S. Cl 2041/209, 204/210 [51} lnt.Cl B0lr 3/00, C23g 5/68 [50]Field of Search 204/209,

[56] References Cited UNITED STATES PATENTS l,5l7,910 12/1924 Kirschneru204/210 2,240,265 4/1941 Nachtman 204/210 X 2,439,858 4/1948 Muddiman etal 204/209 FOREIGN PATENTS 576,313 3/1946 Great Britain 204/209 OTHERREFERENCES Stoltz et al., The Electrochemical Society, Preprint 84-26,pages 283, 285, 290 are relied on Primary Examiner.lohn H. MackAssistant ExaminerR. J. Fay Attorney-Sughrue, Rothwell, Mion, Zinn &Macpeak ABSTRACT: An apparatus for the continuous production of tinplate sheet metal including a spool of sheet metal, an unrolling devicecarrying the spool, a strip of sheet from the spool, a driving deviceadvancing the strip, a welding device, an accumulator for the strip, atensioning device composed of a braking means and a traction means formaintaining the strip taut during its passage in the apparatus, adegreasing device, a pickling device, rinsing vats, an electric tinningdevice, for applying a tin coating on the strip, a drying device, arollers smoothing device into which the strip of metal sheet passes, are-fusing device of the tin coating, a hole detector and a guillotinefor cutting the strip.

I 1 19a. 49 49b PATENTEU DEC 1 4 an SHEET 1 or 2 PATENTED DEC] 412mSHEET 2 OF 2 APPARATUS FOR THE PRODUCTION OF FLAT METAL SHEETS,PARTICULARLY TEN PLATE SHEETS This invention relates to apparatus forthe production of flat metal sheets, particularly tin plate sheets.

It is known that in general, thin metal sheets or strips aremanufactured from a metal ingot which is subjected to several hot orcold rolling operations, possibly preceded and/or followed by otheroperations, such as annealing, pickling and tinning, depending on theintended final use of the metal sheet.

In spite of the perfection of the machines used and in spite of all thecare taken in the carrying out of the operation, the production ofperfectly flat metal sheets required for certain uses always constitutesa problem which has not previously had a satisfactory solution.

Generally, the metal sheets still have faults which affect theirflatness and which can be classed according to two principal groups.First of all certain faults are constituted by portions of geometricallydevelopable surfaces and are due to a difi'erence of uniform lengthbetween the grains of each of the faces of the metal sheet; in thiscategory are classed mainly the defects appearing in the form of ageneral bending in the length or in the width. Consequently, certaindefects which result from an unequal distribution of material areconstituted by portions of geometrically nondevelopable surfaces; amongthese are the ribbing along the edges or at the center projections oraligned hollows or more or less apparent ribbings, often disposed in afishbone arrangement. Whatever their nature or position in the sheetmetal, these defects are annoying, not because of their effect on theappearance of the sheet, but also because of their bad influence on thefinal use of the metal sheet for the fabrication of certain articlesrequiring an absolutely flat metal sheet. in all ways the defects reducethe quality of the metal sheet and occasionally reduce the sellingprice. This has led to investigations being made to eliminate thesedefects in flatness of metal sheets.

For this purpose, metal sheets are often subjected to a smoothingoperation which is generally carried in a roller smoothing device.

Such a rolling device comprises two series of motor driven workingrollers whose axes are disposed in two planes forming a small anglebetween each other, the successive rollers of a series partly occupyingthe successive intervals of the rollers of the other series. The stripof sheet metal to be smoothed is engaged between the two series ofrollers whose action is to impose on the strip a succession of alternateflexings according to the arcs of contact between the strip and therollers; these flexings progressively diminish from the entrance to thesmoothing device up to the exit and this effect is obtained by asuitable arrangement of the rollers. The efficacy depends on the numberof rollers and on their diameter which does not generally exceed 200times the thickness of the sheet metal.

In practice, this type of smoothing shows that its effectiveness if itis real to correct the developable faults is minimal as far as concernsthe nondevelopable faults, since the correction of the latter requiresthe application of a tension to the strip during its passage in thesmoothing device. The effects of the tensions are superimposed on thosecaused by the alternate flexings, and the combination of the tractionand the alternate flexings result in imposing on the sheet metal aslight permanent extension necessary for the correction of the flatness.

But in this case it is necessary to avoid the sliding of the rollers onthe sheet metal, and for this purpose the rollers must have a peripheralspeed precisely adjusted to the speed of advancement of the sheet metal.Such adjustment is very difficult if not impossible to carry outsimultaneously for all the rollers in view of the fact that theperipheral speed is identical for all the rollers since they areintegral with the same drive motor and that the speed of the stripincreases at each passing of a roller as a result of the elongationwhich it undergoes; the result of this is a difference of speed betweenthe roller and the strip which is in many cases prejudicial to the goodfinish of the sheet metal.

This known smoothing has not yet been applied in a tin plate productionline.

According to the present invention there is provided apparatus for thecontinuous production of tin plate sheet metal by electrolyte depositionof tin on a sheet metal which is unrolled from a spool and is maintainedtaut during the whole of its passage in the apparatus comprising adevice for tensioning the strip mainly constituted by a traction means,a degreasing device, a pickling device, an electrolytic tinning deviceand a device for refusing the coat of tin, and a roller smoothing devicein which the strip of sheet metal passes.

In accordance with one feature of the invention, the roller smoothingdevice is situated between the electrolytic tinning device and thedevice for refusion of the tin.

In accordance with a further feature of the invention, the smoothingrollers are idly mounted, that is to say are not provided with any drivemeans.

The invention also provides apparatus for the continuous production offlat sheet metal by passing between the smoothing rollers a strip ofsheet metal unrolled from a spool kept taut for all of its passagebetween the smoothing rollers and specially of a strip of sheet metalhaving undergone known cold working rolling under the name of skin-pass"characterized in that the said smoothing rollers are idly mounted.

The invention will now be described in greater detail by way of examplewith reference to the accompanying drawings in which:

FIG. 1 shows a diagrammatic view of apparatus for the continuousproduction of tin plate in accordance with the invention, and

FIG. 2 is a diagrammatic view on a larger scale of the smoothing devicewith idle rollers.

The apparatus for the production of tin plate by electrolytic depositionof tin comprises an unrolling device 1 carrying a spool of sheet metal 2unrolling in the form of strip 3 which is advanced in the direction ofthe arrows X by means of a driving device 4 placed after a weldingdevice 5; the strip then arrives in a depression 6 forming anaccumulator where it comprises a loop 30. At the exit of the depression6 the strip passes into a braking means 7, comprising the first part ofa tensioning device, the second part of which comprises traction means 8situated towards the end of the line.

After the braking means 7, the strip travels through a series of knowndevices mainly consisting of a hole detector 9, a thickness gauge 10,degreasing, rinsing and pickling vats 11, a brushing vat l2,electrolytic, tinning and rinsing vats l3, and a drying device 16. Atthe exit, the tinned strip 3 travels across a smoothing device 14, adevice for the refusion of the tin l5 and the traction means 8; then itpasses through a hole detector 21 and forms a loop 3b before arriving ata guillotine 17 which cuts it into sheets of given length which thenundergo other treatments before storage.

The roller smoothing device 14 (FIG. 2) comprises two series of idleroller 18 and 19, that is to say rollers not driven. The spindles of theidle rollers 18 turn in bearings 18a all fixed to a stringer 18bintegral with the frame 20, and the spindles of the idle rollers 19 turnin bearings 19a fixed to a stringer 19b also integral with the frame 20.Since the planes containing the axes of the idle rollers 18 and 19respectively make between each other a very small angle, the strip 3which travels in the direction of the arrow X under the action oftraction makes the idle rollers turn. At the entrance into the devicethe strip undergoes a more pronounced flexing than at the exit.

At smoothing device such as that just described is advantageous since itdoes not have any complex controls as the known smoothing devices and itis not necessary to provide a system for regulating the speed of therollers according to the linear speed of the strip; the device is alsoless difficult to run and costs less than a smoother with motor drivenrollers.

Furthermore, it has been estimated that the device is able to removeeven the nondevelopable faults and that there is no danger of a ruptureof the strip in the course of operation because of the low inertia ofthe rollers; furthermore contrary to a currently spread opinion, theeffects of smoothing are not decreased by high advancement speeds of thestrip, so that a smoothing device in accordance with the invention canbe atrained which can exceed a speed of 250 meters per minute.

What I claim is:

1. An apparatus for the continuous production of perfectly plane tinplate sheet metal comprising a spool for strip sheet metal, an unrollingdevice carrying said spool, a driving device advancing said strip, awelding device, an accumulator for said strip, a tensioning devicecomposed of a braking means and a traction means for maintaining saidstrip taut during its passing in the apparatus, a degreasing device, apickling device, rinsing vats, an electrolytic tinning device forapplying a tin coating to said strip, a drying device, a rollers levelerconsisting of idly mounted rollers horizontally disposed in two sets,one above the other, in a staggered relationship to each other, each ofsaid rollers being of substantially the same diameter, and between whichsaid strip of sheet metal travels under traction and undergoes alternateflexing so as to correct the flatness of said strip under traction, areflowing device for said tin coating, a hole detector, and a shear forcutting said strip, said rollers leveler being located between saidelectrolytic tinning device and said reflowing device for said coating,

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